so you mean that they can do 190-200 mph with only 450 hp?

 

Yep. In spite of the apparently huge size (frontal area) of a Cup car, their Cd (drag coefficient)is probably about that of a C5 Vette (.30 or maybe a tad more or less). A 450 hp Vette, with a little work can go about as fast, especailly if that was the target speed for aero work.

NASCAR doesn't want them over 200, so they "massage" (aka "**** with") the restrictor plate hole size (= power) and the aero package (=drag) to hold the speeds down. My guess has always been that it's a liability insurance thing, with 200 mph being the magic number. Maybe not.

If they allowed the 800 or so hp engines, the cars would be faster, but drag rises exponentially, so maybe 20 mph or less faster. It now takes a "plate" car almost 2 laps or 5 miles to get to speed. With an extra 300-350 hp they'd get there much quicker.

 

ok...i see now!

thanks

 

Nascar decided to use the plates after a wreck in talladega were bobby allison flew up into the fence...yall remember that?..it was the spring race in 89 IIRC...since then NASCAR has come leaps and bounds in the reguard of keeping the cars on the ground...92-93 the roof flaps came out (i remember takin a feild trip to roush racing when they were in developemnt) then afew years later the strips along the side of the cars to stop the air from goin over the car when its sliding sideays...i really think that they have advanced enough that NASCAR can experiment with no plates/and or smaller carbs...

the 500 last weekend was a "taste" of what could be...think about it this way....in the 500 the pack was spread thin..that was becasue the tires were softer and the was more rear downforce, meaning the car would push like a dumptruck when the tires wore out...so the drivers would have to breathe the throttle to get the car to stick...so handling became the number 1 goal...with the old package (strip in the roof and the wickerbill on the spoiler and harder tire) the cars could run wide open becasue the increased front downforce... so the cars were stable but you didnt really have to worry about handling per say...
so if you unrestrict the motors then EVERYONE would have to lift in the corners (kinda like a 2 1/2 mile atlanta)...so dnw the straits the speeds would be 220-230 mph but the corner speeds would remain around 185 or so....so the pack would be thinly spread like last weekend, only the strait line speed would be up..

think back to the mid-late 80's 500's....there wernt big packs, there werent "big ones"...like i said it would be a 2 1/2 mile atlanta....the cars would be in the hands of the driver NOT THE AIR...and i think it would really kick *** and be safer for the drivers, obviously the fencing would have to upgraded, but thats a minor detail...

about 3 years ago DEI went to talledega and "tested" an unrestricted motor there....top speed was 232 and corner speed was 202...that would be a hellucva ride

 

ohhh yea i got my info from THE ONLY PLACE THAT SELLS WINSTON CUP PARTS


www.musclemotorsports.com.


the only cam specs that are secret are the valve timings...the lift and duration, arent kept a secret...they cant be becasue nascar mandates those figures for each track...engine builders can play with the valve timings within the set guidlines all they want

and if you can show me a flat tappet lifter that can spin to 9,300 all day with out floating or failing, then you are a bad as...

they ALL use solid rollers,...call NBC and ask benny parsons...cuz thats who i got my info from...then the link i posted above sealed the deal

you really think that nextel cup motors are gonna use a 110 dollar cam and lifter set?....the heads alone are 4 grand to build, and there gonna use a POS flat tappet cam...comon...

check out that link i posted...15,000-20,000 for a FRESHLY BUILT CUP MOTOR and then there gonna jack up the price by converting to a soild roller cam...
they all run solid rollers....im sorry but there isnt a flat lifter/cam that will take that type of abuse....or any kind or hydraulic lifter
and being the builders 100's of thousands of dollars getting every last bit of friction out of the motor there gonna use a flat tappet lifter....

there gonna use a flat lifter with 1000 bucks JUST IN ROCKERS!!...
4 grand in head work and a flat lifter


with a 4.125 bore and a 3.335 stroke thats 356.6 cubes....


ill give roush a call today to try to get some info

done with my rant..

 

I'm hoping you are just trying to pull our legs with your posts. There is a chance you might be serious. If you truly believe all you said, I understand that you want to rant; it's tough swimming upstream!

Good luck to you.

 

My91,

Benny lives in my neighborhood... and I highly doubt he'd give you that much incorrect information, unless he was just telling you what you wanted to hear. I'm certainly not saying I think you're lying, simply misinformed though (if we're talking about actual current specs and not packages from years ago).

Jon is correct... and look to see packages running ~9500-9600rpm in the future... & the lift is typically greater than what you quoted as well . Head cost will obviously fluctuate, as alot of shops just machine their own in-house as opposed to buying them elsewhere. When they do acquire a new head from elsewhere.. they usually just digitize it & if you're (the porter) smart, you'll get all of the $ you ever want out of that head up front.

The musclemotorparts guys are nice, but I wouldn't quote any of the info on their pages, last I saw it was pretty outdated .

Interesting topic however... the current cup powerplants really are amazing feats of engineering IMO. The aero stuff is pretty interesting as well, bannana shaped racecars and all

-Phil

 

I'm in awe of those guys.

FWIW, Cup engines run about the same piston speeds as 19,000 rpm F1 engines. (Half the Cup stroke on the F1s).

Even more interesting (to me) is to check torque per litre (or cubic inch) at power peak rpm for 900 hp 3.0L BMW F1 engine and 800 hp 5.87 L Cup engine. That indicates to me how efficient these air pumps are at hp peak. Assuming hp peak is at say 95% of max rpm, both engines have about 82-86 lb-ft /Litre at hp peak.

Of course the F1 engine subjects the pistons to 10000 gs at max speed vs about 5000 gs for the Cup engine. Bet the F1 pistons and pins are LIGHT and the approximately 3.2 inch long rod is VERY strong.

 

i remember the first time i ever went in there, i bet i was in there for two hours just looking at stuff. they prolly thought i was trying to steal some stuff!

 

All of the discussion is interesting. Here are the things I know FOR SURE:

Nextel Cup uses flat tappet cams, not rollers. (Roller setups are allowed in Trucks and Busch--if you hear these idle in person you can tell the difference)

Compression ratio is limited to 9.5:1 in all 3 series, I don't know where you guys are getting this 12.5 and 13:1 nonsense.

Rocker ratios are in excess of 2:1, more like 2.2:1.


$4000 for heads..what are you kidding me? Maybe in the truck series. A complete ready to run Busch motor including oiling system (a competitive one) is around $50,000. I know this for a fact..or you can just give Katech a call. And you can imagine that Cup motors are not is the same $$$ ballpark.

 

It's 12 to 1 not 9.5 to 1 on Nextel Cup cars!

Busch was the low compression class before and WC was even 14+ to 1 before the rules.

 

Same here buddy! If I'm ever bored on a Saturday, up to their shop I go

Ok, now the tech part.

At the shop, we turn the cars up to around 9900-10k RPM's on the dyno. All with their flat tappet cams! We're limited, in Cup, to a 4.185" Bore. Stroke varies track to track. CR is ~12:1 Gears are from 2.93 (Superspeedways) to 6.50 (Martinsville). We load up about 15-20 gearsets for a track, all in their own carriers. Massive oil cooling is all that keeps those 9"s together.

I heard Newman was running a 750 CFM not 800. Oh well though, the secret's out

I work at the Statesville shop, they build the motors in Concord. So I don't know the exact specs of the engines. I couldn't/wouldn't get too technical with ya'll anyway

 

I did some research, I was indeed wrong about the CR. It is 12:1, but it is also 12:1 for Busch series cars now also.

Here is a quote from Jeff Hammond.

 

dude, you need to get me a job up there!!!

 

It mostly has to do with aero then gearing. I'm pretty sure that if they had the choice, they would go with better aero.